Readers’ wildlife photos

Reader Bruce Lyon sent some nice photos of wild spider monkeys (Ateles) from Costa Rica, as well as some information (his comments are indented):

During my recent trip to Costa Rica we spent time at a functioning farm/ecotourist lodge) that has lovely cabins set along a river. This farm is crawling with both spider and howler monkeys and is the best place I have yet come across for spider monkeys because they are so abundant and so tame. Spider monkeys are not always tame and will show their displeasure at humans on the ground under them by throwing things like fruit or branches and then quickly fleeing. The monkeys at this farm (called Cañas Castilla in the event that any readers are looking for fun places to visit) have the run of the place, and are even allowed to harvest as many oranges as they want from the orange groves.

I’m not sure which species these are, but I know a reader will enlighten me.

An orange thief—in both meanings of the phrase.

The monkeys are social and we often see fairly large groups moving through the trees. The name spider monkey is wonderfully apt given their long hairy limbs. The long arms are useful for the monkeys’ primary mode of travel—using their arms to swing from branch to branch (“brachiating”). It is amazing how quickly they can cover ground. In addition to brachiating, they also make spectacular leaps to cross gaps between trees (I estimate some leaps to cover 10 feet).

Not an action photo of an animal brachiating, but simply a monkey resting in a silly pose, but the photo does give a sense of the reach their long arms give them:

Spider monkeys also have prehensile tails and they can hang from the tail alone, which they do while dangling to get fruit. I photographed this monkey, nicely showing off its prehensile tail wrapped around a branch, from the front porch of our cabin:

Below: A baby riding on its mom. Really small babies are carried much of the time but older babies often move through the trees themselves and only get help from mom when needed. Mom helps these older youngsters in two ways. For leaping across big gaps, the baby climbs aboard, holds on tight and mom does the leap for both of them. For smaller gaps a mother sometimes makes a bridge that the baby can crosse — the mom’s tail grabs a branch on one side of the gap while her hands hang on to something on the other side of the gap, and the kid then scoots across. This past trip I saw this happen twice; in both cases the kids looked like they were going to try to make a leap but then chickened out. The moms, who had been ahead, then came back and formed a bridge for the kid to cross. These are good moms!

Check out the tail on this mom: it is naked on the underside, presumably for better grip for wrapping around branches.

I watched a large troop moving through the trees along the river and it soon became clear that every animal was using the exact same cross point to leap between two trees. This gave me lots of chances to photograph animals in mid leap since I could predict where they would cross. The light was pretty bad but the photos still show what the leaps are like.

Below is a mother and baby about to leap. I love the expression on the baby: excited or freaked out?

Wonderful. One of my texts on human evolution explains that New World monkeys are generally red-green color blind (an exception is the howler monkey), and their noses are flatter with nostrils that point ~ sideways. You can see that feature in some of the terrific pictures above. Old World monkeys have tri-color vision, and their noses are more narrow with nostrils that point downwards. So we humans are descended from OWM!. I know of course that it is more proper to say we share a common ancestry.

Great pictures, especially the mid-jump captures. I’ve been to Cañas Castilla. You can see quite a bit of wildlife there at times. It’s run by a very nice Swiss couple. They make some pretty good stone oven pizza too.

One of my schemes is to run off to some place that this for a vacation with my wife, leaving the kids at home to scrounge for food. I would then mainly pursue the inscrutable machinations of my soul, which is to look for cool bugs.

Oops—I should have provided the name. According to my mammal field guide, these are Central American Spider Monkeys (also called Geoffroy’s Spider Monkey (Ateles geoffroyi. Wikipedia indicates there are seven species of spider monkeys, a couple of which are in deep conservation doo doo.

The red cap reminds me of a young Patas monkey I looked after for a year or so living in the Sudan. He use to ride around sitting on my shoulder or on top of my head. I had a permission from the Minister of Tourism and Wildlife to export Basilio but then his canine teeth started getting longer. About that time an older female showed showed up with a bad cut. After that healed I took them several miles away from human population and turned them loose. Basilio’s photo remains on my wall. What a pal.
Prehensile tails are cool.

why is it that prehensile tails are so common in South America but rare elsewhere? Not just monkeys, but independently also ‘porcupine’, anteater, opossum and I think even coati’s tails are partially prehensile?
Is there something in the Neotropic environment missing elsewhere?

Lots of the Aussie possums have prehensile tails, with the same naked underside. We have the brushtail possum here in NZ – I lifted one’s tail once, and it gently curled around my finger. Surprisingly warm, too.

This doesn’t answer why, but Old World monkeys have ischial callosities (roughened butt pads) for gripping branches instead of prehensile tails. Not sure of the significance, been trying to slip that into a conversation for 20 years :)